Apparatus and method for wastewater treatment

Abstract

A method for treating wastewater. The method comprises: providing a first dose of air to aerate a medium bed; supplying a dose of wastewater to the aerated medium bed; allowing nitrification of the wastewater to occur; allowing denitrification to occur; and providing a subsequent dose of air to the medium bed. A combined aerobic and anaerobic treatment apparatus. The apparatus comprises: a medium bed; a wastewater conduit in fluid communication with the medium bed; an air conduit in fluid communication with the medium bed; and where the combined aerobic and anaerobic treatment apparatus is configured to first allow a dose of wastewater in the medium bed to undergo a nitrification process which is generally aerobic, and then second allow the dose of wastewater in the medium bed to undergo a denitrification process which is generally anaerobic. An apparatus for treating wastewater. The apparatus comprises: means for providing a first dose of air to aerate a medium bed; means for supplying a dose of wastewater to the aerated medium bed; means for allowing nitrification of the wastewater to occur; means for allowing denitrification to occur; and means for providing a subsequent dose of air to the medium bed.

1. A method for treating wastewater comprising:
 blowing a first dose of air into a volume of generally liquid water-free space located above a medium bed; 
 supplying a dose of wastewater to the aerated medium bed; 
 allowing nitrification of the wastewater to occur; 
 allowing denitrification to occur; and 
 blowing a subsequent dose of air into the volume of generally liquid water-free space located above a the medium bed. 
 
     
     
       2. The method of  claim 1 , wherein the providing a subsequent dose of air occurs after an amount of time has elapsed since the supplying a dose of wastewater. 
     
     
       3. The method of  claim 2 ,
 wherein the dose of wastewater is about 0.3 gallons times the surface area of the bed (ft 2 ) to about 6.7 gallons times the surface area of the bed (ft 2 ). 
 
     
     
       4. The method of  claim 2 , wherein the amount of time is about 15 minutes to about 4 hours. 
     
     
       5. The method of  claim 1  further comprising:
 providing at least one dose of air to the medium bed such that microorganisms in the bed that assist in nitrification of the wastewater are not adversely affected. 
 
     
     
       6. The method of  claim 1 , wherein the first does of air is about 2 to about 40 scfh/ft 2  for about 15 minutes to about 4 hours. 
     
     
       7. The method of  claim 1 , wherein the subsequent dose of air is about 2 to about 40 scfh/ft 2  for about 15 minutes to about 4 hours. 
     
     
       8. The method of  claim 1 , wherein the subsequent does of air is about 8 to about 60 scfh/ft 2  for about 15 minutes to about 4 hours. 
     
     
       9. The method of  claim 1 , further comprising, after supplying a dose of wastewater to the aerated medium bed:
 ponding water on the surface of the bed for a period of time. 
 
     
     
       10. The method of  claim 1 , wherein the medium bed is aerated such that oxygen makes up at least 10% by volume of gas located at the interstices of the medium. 
     
     
       11. The method of  claim 1 , wherein the medium bed is aerated such that oxygen makes up at least 15% by volume of gas located at the interstices of the medium. 
     
     
       12. The method of  claim 1 , wherein each dose of air moves in the same direction as the dose of wastewater. 
     
     
       13. The method of  claim 1 , further comprising:
 dewatering the media with the subsequent dose of air. 
 
     
     
       14. A combined aerobic and anaerobic treatment apparatus comprising:
 a medium bed; 
 a volume of generally liquid water-free space located above the medium bed; 
 a wastewater conduit in fluid communication with the medium bed; 
 an air conduit in fluid communication with the medium bed; and 
 wherein the combined aerobic and anaerobic treatment apparatus is configured to (a) blow a first a dose of wastewater into the volume of generally liquid water-free space located above the medium bed, and then (b) allow the first dose of wastewater to undergo a nitrification process which is generally aerobic, and then (c) allow the first dose of wastewater in the medium bed to undergo a denitrification process which is generally anaerobic. 
 
     
     
       15. The combined aerobic and anaerobic treatment apparatus of  claim 14 , wherein the medium bed is located in a container; and wherein a wastewater exit conduit is in fluid communication with the medium and in fluid communication with a leech field. 
     
     
       16. The combined aerobic and anaerobic treatment apparatus of  claim 14 , wherein the medium bed is located in an open bottomed container; and wherein the medium bed is in fluid communication with soil underlying the open bottomed container. 
     
     
       17. The combined aerobic and anaerobic treatment apparatus of  claim 14 , further configured to pond wastewater at the surface of the medium bed for a period of time. 
     
     
       18. The combined aerobic and anaerobic treatment apparatus of  claim 14 , further configured such that the dose of air moves in the same direction as the dose of wastewater. 
     
     
       19. The combined aerobic and anaerobic treatment apparatus of  claim 14 , further comprising an air mover in fluid communication with the medium bed and configured to provide a dose of air to the medium bed. 
     
     
       20. An apparatus for treating wastewater comprising:
 means for blowing a first dose of air into a volume of generally liquid water-free space located above a medium bed; 
 means for supplying a dose of wastewater to the aerated medium bed; 
 means for allowing nitrification of the wastewater to occur; 
 means for allowing denitrification to occur; and 
 means for blowing a subsequent dose of air into the volume of generally liquid water-free space located above the medium bed. 
 
     
     
       21. The apparatus of  claim 20 , wherein each dose of air moves in the same direction as the dose of wastewater.